DEVICE AND METHOD FOR SUPPLYING AND DISCHARGING AIR TO AND FROM SAND TANK FOR MOLD FORMING MACHINE

摘要

A device and a method for supplying and discharging air to and from a sand tank for a mold forming machine use a reduced number of on-off valves and are configured so that sand is prevented from adhering to the inside of an air discharge valve when air is discharged. A device for supplying and discharging air to and from a sand tank for a mold forming machine is provided with: a sand tank for the mold forming machine; a porous body provided within the sand tank so as to be separated from the inner surface of the sand tank; a hollow chamber formed by the outer surface of the porous body and by the inner surface of the sand tank; a seal member mounted to the peripheral edge of the front end of a sand loading nozzle of the sand tank and expanded when compressed air is introduced into the inner space of the seal member; a pilot-operated air supply and discharge valve communicated with the hollow chamber and serving for both air supply and air discharge; and an on-off valve communicated with the pilot-operated air supply and discharge valve and with the inner space of the seal member.